Finding of Infringement Under the Doctrine of Equivalents Affirmed Where the Infringer Admitted to the FDA that its Substitute Ingredient Performed the Same Function as the Claimed Ingredient

In this ANDA case involving claims directed to a hydrogel for topical treatment, the district court found the claims to be infringed under the doctrine of equivalents and that Glenmark had not proven the claims to obvious. Glenmark appealed both grounds.

First, as to infringement under the doctrine of equivalents, Glenmark argued that the equivalent ingredient in its product did not meet the “function” part of the function, way, result test, and therefore could not be an equivalent, because there was no evidence that the ingredient in Glenmark’s product acted as a penetration enhancer in its composition, unlike the corresponding claimed ingredient. Glenmark, however, had represented to the FDA in its ANDA submission that is ingredient did act as a penetration enhancer, and, based on this representation, the district court correctly found that the ingredient did perform the same function and therefore was an equivalent.

Glenmark further argued that the doctrine of equivalents could not apply, because its product would be ensnared by the prior art. The district court applied the hypothetical claim test, which Glenmark argued was applied erroneously, because the court limited the scope of the penetration enhancer ingredient in the hypothetical claim. The Federal Circuit held that there was no error, because the hypothetical claim analysis requires that the claim literally recite the accused product and there is no requirement that the claim capture all possible penetration enhancers.

Glenmark also argued that prosecution history estoppel precluded application of the doctrine of equivalents. Here, the prosecution history did not evidence a clear and unmistakable surrender of claim scope, but rather was a clarifying amendment to a dependent claim to make clear that, in the dependent claim, the amount of a certain ingredient was “from more than 0% to 3%,” and because the dependent claim had to be narrower than the dependent, this amendment was merely clarifying, not narrowing.

Second, as to the issue of obviousness, Glenmark argued that the district court erred by finding that there was no basis for combining the references, based on the finding that the swapping of ingredients in complex chemical formulations is anything but “routine.” The Federal Circuit agreed with the district court and affirmed the judgment of the district court.

Intendis GMBH v. Glenmark Pharmaceuticals Inc. USA, Case No. 2015-1902 (May 16, 2016); Opinion by: Moore, joined by Prost and Taranto; Appealed From: United States District Court for the District of Delaware, Robinson, J. Read the full opinion here.